<?php
/**
 * CDbColumnSchema class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright 2008-2013 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * CDbColumnSchema class describes the column meta data of a database table.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package system.db.schema
 * @since 1.0
 */
class CDbColumnSchema extends CComponent
{
    /**
     * @var string name of this column (without quotes).
     */
    public $name;
    /**
     * @var string raw name of this column. This is the quoted name that can be used in SQL queries.
     */
    public $rawName;
    /**
     * @var boolean whether this column can be null.
     */
    public $allowNull;
    /**
     * @var string the DB type of this column.
     */
    public $dbType;
    /**
     * @var string the PHP type of this column.
     */
    public $type;
    /**
     * @var mixed default value of this column
     */
    public $defaultValue;
    /**
     * @var integer size of the column.
     */
    public $size;
    /**
     * @var integer precision of the column data, if it is numeric.
     */
    public $precision;
    /**
     * @var integer scale of the column data, if it is numeric.
     */
    public $scale;
    /**
     * @var boolean whether this column is a primary key
     */
    public $isPrimaryKey;
    /**
     * @var boolean whether this column is a foreign key
     */
    public $isForeignKey;
    /**
     * @var boolean whether this column is auto-incremental
     * @since 1.1.7
     */
    public $autoIncrement = false;
    /**
     * @var string comment of this column. Default value is empty string which means that no comment
     * has been set for the column. Null value means that RDBMS does not support column comments
     * at all (SQLite) or comment retrieval for the active RDBMS is not yet supported by the framework.
     * @since 1.1.13
     */
    public $comment = '';

    /**
     * Initializes the column with its DB type and default value.
     * This sets up the column's PHP type, size, precision, scale as well as default value.
     * @param string $dbType the column's DB type
     * @param mixed $defaultValue the default value
     */
    public function init($dbType, $defaultValue)
    {
        $this->dbType = $dbType;
        $this->extractType($dbType);
        $this->extractLimit($dbType);
        if ($defaultValue !== null)
            $this->extractDefault($defaultValue);
    }

    /**
     * Extracts the PHP type from DB type.
     * @param string $dbType DB type
     */
    protected function extractType($dbType)
    {
        if (stripos($dbType, 'int') !== false && stripos($dbType, 'unsigned int') === false)
            $this->type = 'integer';
        elseif (stripos($dbType, 'bool') !== false)
            $this->type = 'boolean';
        elseif (preg_match('/(real|floa|doub)/i', $dbType))
            $this->type = 'double';
        else
            $this->type = 'string';
    }

    /**
     * Extracts size, precision and scale information from column's DB type.
     * @param string $dbType the column's DB type
     */
    protected function extractLimit($dbType)
    {
        if (strpos($dbType, '(') && preg_match('/\((.*)\)/', $dbType, $matches)) {
            $values = explode(',', $matches[1]);
            $this->size = $this->precision = (int)$values[0];
            if (isset($values[1]))
                $this->scale = (int)$values[1];
        }
    }

    /**
     * Extracts the default value for the column.
     * The value is typecasted to correct PHP type.
     * @param mixed $defaultValue the default value obtained from metadata
     */
    protected function extractDefault($defaultValue)
    {
        $this->defaultValue = $this->typecast($defaultValue);
    }

    /**
     * Converts the input value to the type that this column is of.
     * @param mixed $value input value
     * @return mixed converted value
     */
    public function typecast($value)
    {
        if (gettype($value) === $this->type || $value === null || $value instanceof CDbExpression)
            return $value;
        if ($value === '' && $this->allowNull)
            return $this->type === 'string' ? '' : null;
        switch ($this->type) {
            case 'string':
                return (string)$value;
            case 'integer':
                return (integer)$value;
            case 'boolean':
                return (boolean)$value;
            case 'double':
            default:
                return $value;
        }
    }
}
